(1) Field of the Invention
This invention concerns a device for feeding up sheets in a sheet collating machine, wherein preferably sheets of paper in the form of stacks are positioned in bins which are located in the longitudinal direction of the machine below a conveying path which is equipped with conveying members, with a feed-up device being provided for each bin and comprising one or more feed-up wheels which are connected to a driving means, each feed-up device being pivotal between a lowered position, in which the feed-up wheels engage the stack of sheets and feed up one sheet at a time towards the conveying path, and a raised position in which the feed-up wheels are disengaged from the stack.
(2) Description of the Prior Art
A collating machine for sheets, primarily paper sheets, comprises a plurality of bins for stacks of sheets, said stacks containing sheets of the same or different types. In collating sheets from individual stacks to form a sheet set one sheet at a time is fed from the respective stack for collecting on a conveying path. In feeding up the sheets from the respective stacks an indication is given if any sheet at all is fed up onto the conveying means. If a sheet is not fed up onto the conveying path from one of the stacks, the machine will deliver a signal which indicates that the set of sheets is incomplete and the machine will stop.
In the known machines a feed-up device is disposed in conjunction with each bin and exhibits feed-up wheels which are positioned such, that they engage the upper sheet in a stack of sheets that is located in the bin. When the feed-up wheels are rotated the upper sheet of the stack is fed upwards between a press roller and a belt running above this roller. The sheets which have been fed upwardly are gripped there by the belt and the rotating press roller and are fed along the conveying path. The feed-up devices at the respective bins can be raised mechanically by a lifting device which is common to all of the feed-up devices. Also, each feed-up device can be lifted manually with a specific means, which can occur with respect to the bins in which no stacks are disposed during a collating procedure. In the known machine the feed wheels in the feed-up devices are driven by one and the same drive motor.
In the sheet collating machine known up to now there is a danger of so-called additive overfeeding of sheets from one and the same bin, which occurs by the feed-up device withdrawing sheets from the stack in the bin even after the first sheet has been delivered from the feed-up device. The explanation of this is that the machines of the prior art do not exhibit control means which influence the feed-up device when a sheet begins to protrude between the press roller and the belt lying thereabove in the conveying path.